David Stark, 61, who runs online songwriters’ resource SongLink International, funded the Heritage Foundation plaque and attended its unveiling at Epstein’s former offices in Sutherland House, Soho, on Sunday.

Mr Stark then hosted a celebratory lunch at the Marriott Hotel, in King Henry’s Road, Swiss Cottage, attended by some of Epstein’s former friends and TV actor Andrew Lancel, who is set to play the late impresario in a West End show opening later this month.

Epstein, who lived in Swiss Cottage upon moving to the capital from Liverpool, died at the height of The Beatles’ fame from an overdose of sleeping pills in 1967.

He was later described by Sir Paul McCartney as “the fifth Beatle”.

Mr Stark, of Belsize Crescent, said: “As a lifelong Beatles fan I’m delighted to be involved with this official commemoration of Britain’s most famous music manager.

“Epstein’s signing of the Fab Four in early 1962 developed into the greatest story in music and showbiz history.”